Problem: Simplify the following expression: $p = \dfrac{n^2 + 3n - 40}{n + 8} $
Solution: First factor the polynomial in the numerator. $ n^2 + 3n - 40 = (n + 8)(n - 5) $ So we can rewrite the expression as: $p = \dfrac{(n + 8)(n - 5)}{n + 8} $ We can divide the numerator and denominator by $(n + 8)$ on condition that $n \neq -8$ Therefore $p = n - 5; n \neq -8$